Cervical distraction/implant delivery device

ABSTRACT

Systems for distracting a facet joint and positioning a permanent implant in the joint are disclosed. The implants serve to retain a distracted position of the facet joint which is achieved with positioning of the leading end of a distraction tool in the facet joint and then distracting or enlarging the joint a desired amount. The permanent implant could be part of the distraction mechanism which can be separated from the delivery tool once the joint has been distracted or an auxiliary implant may be positioned before the distraction mechanism is removed from the distracted joint. The permanent implants can be solid, mechanical devices that may have fixation means thereon to hold them in place or injected fluids such as hydrogels or fluids confined within balloons.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.12/559,193 filed Sep. 14, 2009 and entitled Cervical Distraction/ImplantDelivery Device (the '193 application). The '193 application is acontinuation-in-part of U.S. application Ser. No. 12/455,814 filed Jun.5, 2009, now U.S. Pat. No. 8,361,152, and entitled Facet Joint Implantsand Delivery Tools (the '814 application). The '814 application is acontinuation-in-part of U.S. application Ser. No. 12/317,682 filed Dec.23, 2008, now U.S. Pat. No. 8,267,966, and entitled Facet Joint Implantsand Delivery Tools (the '682 application).

The '193 application also claims priority from: U.S. ProvisionalApplication No. 61/169,601 filed Apr. 15, 2009 and entitled Facet JointImplants and Delivery Tools; U.S. Provisional Application No. 61/109,776filed Oct. 30, 2008 and entitled Facet Joint Implants; and U.S.Provisional Application No. 61/097,103 filed Sep. 15, 2008 and entitledCervical Distraction/Implant Delivery Device.

The '682 application claims priority from U.S. Provisional ApplicationNo. 61/059,723 filed Jun. 6, 2008 and entitled Spine Distraction Device.

The contents of all of the above applications are hereby incorporated byreference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains generally to a cervical distraction device andmore particularly to such a device that cannot only distract a facetjoint but also deliver an implant to the distracted joint.

2. Description of the Relevant Art

Chronic back problems cause pain and disability for a large segment ofthe population. Adverse spinal conditions are characteristic of age.With aging, generally comes an increase in spinal stenosis (including,but not limited to, central canal and lateral stenosis), and facetarthropathy. Spinal stenosis results in a reduction of foraminal area(i.e. the available space for the passage of nerves and blood vessels),which compresses the cervical nerve roots and causes radicular pain.Extension and ipsilateral rotation of the neck further reduces theforaminal area and contributes to pain, nerve root compression, andneural injury. However, neck flexion generally increases the foraminalarea.

Cervical disc herniations predominantly present upper extremityradicular symptoms. The vast majority of these herniations do not havean associated neurological deficit and present pain only. Awell-described treatment for cervical disc herniations is closedtraction. There are a number of marketed devices that alleviate pain bypulling on the head to increase foraminal height.

Cervical disc herniations have been treated with anterior and posteriorsurgery. The vast majority of these surgeries are performed through ananterior approach, which requires a spinal fusion. These surgeries areexpensive and beget additional surgeries due to change in biomechanicsof the neck. There is a three percent incidence of re-operation aftercervical spine surgery.

It is an object of the present invention to provide a minimally invasivedevice and procedure to increase foraminal height to reduce radicularsymptoms for patients with disc herniations.

SUMMARY OF THE INVENTION

In one embodiment, a distraction tool for distracting a facet joint caninclude a handle, a cannula extending from the handle, and a distractionmechanism positioned on a distal end of the cannula and adapted to beplaced in the facet joint. In this embodiment, the handle can be incommunication with the distraction mechanism and actuation of the handlecan cause distraction thereof.

In another embodiment, a distraction mechanism for distracting a facetjoint can be provided. The mechanism can include a head in the form ofan oblong band and an elongate member extending through the head. Theelongate member can be adapted to draw opposing ends of the head towardone another thereby expanding the head.

In still another embodiment, a distraction mechanism can include aplurality of pairs of teeth in pivotal relation with a central core andan elongate member extending through the central core. Actuation of theelongate member can cause distraction of at least one of the pluralityof pairs of teeth.

In still another embodiment, a distraction mechanism can include ahollow elongated body having facet engaging features and an elongatedmember adapted for insertion within the body. Insertion of the elongatedmember can actuate the facet engaging features.

In still another embodiment, a distraction mechanism can include anexpandable receiving portion having upper and lower generally planarelements connected at an end with a living hinge. The distractionmechanism can also include an actuation device adapted to be placedbetween the planar elements. The planar elements can include malleablematerial that conforms to the facet surface upon implantation.

In yet another embodiment, a delivery tool for positioning a distractionmechanism in a facet joint can include a distraction mechanism fordistracting a facet joint and a handle and a cannula connected to oneanother and carrying said distraction mechanism on a distal end thereof.The handle can include means for delivering energy to said distractionmechanism, and said distraction mechanism can be manipulatable toincrease the spacing of said confronting facets thereby distracting saidfacet joint.

A device and technique are disclosed for a minimally invasive surgicalimplantation to reduce radicular symptoms by inserting a distractionmechanism in a facet joint of an affected level of the spine to preservethe physiology of the spine. In particular, embodiments of the presentinvention provide for distracting and translating the cervical spine toincrease the foraminal dimension in extension and neutral positions. Thedistraction mechanism may have a portion which can serve as an implantor it may be a mechanism for facilitating insertion of a separateimplant. When the distraction mechansim is positioned in the cervicalfacet joint, it expands to distract or increase the space between thevertebrae to increase the foraminal area or dimension and reducepressure on the nerves and blood vessels of the cervical spine. Thedevices and techniques disclosed supplement those disclosed in U.S.nonprovisional patent application Ser. No. 11/618,619 filed Dec. 29,2006, entitled Cervical Distraction Device, and U.S. provisional patentapplication Ser. No. 61/059,723, filed Jun. 6, 2008, entitled SpineDistraction Device, which are of common ownership with the presentapplication, the disclosures of which are hereby incorporated byreference.

The implantation procedure may be performed under conscious sedation inorder to obtain intra-operative patient symptom feedback.

After achieving the desired distraction of the facet joint, the distaltip of the distraction tool may be detached from the tool so thedistraction device itself serves as a permanent implant for placement inthe facet joint. The patient is left with the distraction device implantin the facet joint with permanent increased foraminal height. As analternative, the distraction device can be removed from the distractedjoint after a separate or auxiliary insert is positioned in the joint.

While the implant may comprise an inflatable balloon configured to befilled with an inflation medium, e.g. hydrogel or the like, todistribute a compressive load on the articulating surfaces as disclosedin the aforenoted U.S. nonprovisional patent application Ser. No.11/618,619, pursuant to the present invention, the implant may also be amechanical device that does or does not expand or inflate.

The implant is configured to dynamically stabilize or fuse the facetjoint and retain it in an expanded or distracted condition. The implantmaintains a minimal distance between the articulating surfaces and, insome embodiments, allows motion of a first vertebra with respect to asecond adjacent vertebra.

According to the technique of the invention, an expandable ornon-expandable distraction device is inserted in a collapsed state intoa facet joint bounded by first and second vertebrae, and is expandedwithin the facet joint to increase a foraminal dimension associated withthe first and second vertebrae. The implant is installed in a facetjoint located between adjacent cervical vertebrae. The expandableimplant engages the articulating surfaces of the facet joint to increasethe distance between the articulating surfaces.

Further aspects of the invention will be brought out in the followingportions of the specification, wherein the detailed description is forthe purpose of fully disclosing preferred embodiments of the inventionwithout placing limitations thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary isometric of a portion of the human spineshowing a facet joint which may be treated with the devices andtechniques of the present invention to distract the facet joint andretain it in an expanded condition.

FIG. 2 is an isometric similar to FIG. 1 viewed from a differentdirection.

FIG. 3 is an isometric similar to FIG. 2 with a distraction device inaccordance with the present invention having its distal end insertedinto the facet joint and having an implant device releasably held in thedistal end.

FIG. 4 is an isometric similar to FIG. 3 with the implant having beenpositioned within the facet joint to retain the distracted position ofthe joint.

FIG. 5 is a section taken through the spinal column showing implant inposition on bilateral facets.

FIG. 6A is an isometric section with parts removed of a first embodimentof a distraction device in accordance with the present invention.

FIG. 6B is a diagrammatic side elevation of the device of FIG. 6A withthe distal tip of the device positioned within a facet joint.

FIG. 6C is an elevation similar to FIG. 6B with the device expanded todistract the facet joint.

FIG. 7A is a fragmentary isometric of a second embodiment of thedistraction device of the present invention.

FIG. 7B is a side elevation of the device of FIG. 7A having its distaltip of the device inserted into a facet joint.

FIG. 7C is an elevation similar to FIG. 7B with the distal tip expandedto distract the facet joint.

FIG. 8A is an isometric of an expandable tip of a distraction deviceshowing a third embodiment of the present invention.

FIG. 8B is a side elevation showing the device of FIG. 8A positioned onthe distal end of a distraction tool with the device inserted into afacet joint.

FIG. 8C is a side elevation similar to FIG. 8B with the device expandedto distract the facet joint.

FIG. 9A is a fragmentary isometric of the distal tip of a distractiondevice showing a fourth embodiment of the present invention.

FIG. 9B is a side elevation showing the device of FIG. 9A positioned ina facet joint.

FIG. 9C is a side elevation similar to FIG. 9B with the device expanded.

FIG. 10A is an isometric of a fifth embodiment of the device of thepresent invention.

FIG. 10B is an isometric similar to FIG. 10A with the device expanded.

FIG. 10C is a side view showing the device of FIG. 10A positioned on thedistal end of a distraction tool.

FIG. 10D is a side view similar to FIG. 10C with the device expanded asin FIG. 10B and separated from the insertion tool.

FIG. 11A is a fragmentary isometric of a sixth embodiment of the presentinvention.

FIG. 11B is a side view showing the device of FIG. 11A inserted into afacet joint.

FIG. 11C is a side view similar to FIG. 11B with the device having beenrotated with the insertion tool to distract the facet joint.

FIG. 12A is an isometric of the handle of a seventh embodiment of thepresent invention.

FIG. 12B is the distal tip of the seventh embodiment of the handle whichis shown in FIG. 12A.

FIG. 12C is a transverse section of the distal tip as shown in FIG. 12B.

FIG. 12D is a diagrammatic cross-section through a facet joint with thedevice of FIG. 12B positioned therein and having injected a gelsubstance into the facet joint.

FIGS. 13A and 13B are fragmentary isometric views of a tip of adistraction device in accordance with the present invention showing aneighth embodiment of the distal tip of the device.

FIG. 13C is a side view of a tool inserting the device of FIG. 13A intoa facet joint.

FIG. 13D is a side view similar to FIG. 13C with the device of FIG. 13Ahaving been rotated to distract the facet joint and the insertion deviceremoved from the tip which serves as an implant.

FIGS. 13E-13H are respectively the same views as depicted in FIGS.13A-13D, except of a variation of the embodiment depicted in FIGS.13A-13D.

FIG. 14A is an isometric showing the tip of a ninth embodiment of adistraction device in accordance with the present invention.

FIG. 14B is a side view showing the distraction device of FIG. 14Ainserted into a facet joint with an insertion tool.

FIG. 14C is a side view similar to FIG. 14B with a plurality of bladesor spatula elements having been advanced into the facet joint todistract the joint.

FIG. 15A is an isometric of a tenth embodiment of a distraction devicein accordance with the present invention.

FIG. 15B is a side view of the device shown in FIG. 15A on the distalend of an insertion tool and positioned within a facet joint.

FIG. 15C is a side view similar to FIG. 15B with the distraction devicehaving been expanded to distract the facet joint and deliver a permanentimplant into the distracted joint.

FIG. 16A is a side view of an eleventh embodiment of a distractiondevice in accordance with the present invention, showing a wedge option,an elongated member option, and a block option.

FIG. 16B is an isometric of the wedge option of FIG. 16A.

FIG. 16C is a side view of the distraction device of FIG. 16A positionedwithin a facet joint on the distal tip of an insertion tool.

FIG. 16D is a side view similar to FIG. 16B with the distraction deviceexpanded to distract the facet joint and with the insertion tool havingbeen separated therefrom.

FIG. 17A is an isometric of a twelfth embodiment of a distraction devicein accordance with the present invention.

FIG. 17B is a side view of the device of FIG. 17A positioned in a facetjoint and on the end of an insertion tool.

FIG. 17C is a side view similar to FIG. 17B with the device of FIG. 17Ahaving been expanded and the insertion tool separated therefrom to leavethe device as an implant in a distracted facet joint.

FIG. 18A is a diagrammatic fragmentary isometric with parts removedillustrating a thirteenth embodiment of the present invention.

FIG. 18B is a fragmentary diagrammatic vertical section through thedevice shown in FIG. 18A.

FIG. 19A is a fragmentary diagrammatic similar to FIG. 18A showing analternative fourteenth embodiment.

FIG. 19B is a fragmentary vertical section similar to FIG. 18B showingthe alternative embodiment of FIG. 19A.

FIG. 20A is an isometric of a fifteenth embodiment of a distractiondevice in accordance with the present invention.

FIG. 20B is an enlarged fragmentary isometric view of the distal tip ofthe device of FIG. 20A.

FIG. 20C is a diagrammatic vertical section showing the device of FIG.20A inserted into a facet joint.

FIG. 21A is an isometric of a sixteenth embodiment of a distractiondevice in accordance with the present invention.

FIG. 21B is an enlarged fragmentary isometric of the distal tip of thedevice of FIG. 21A.

FIG. 21C is a diagrammatic vertical section showing the device of FIG.21A inserted into a facet joint.

FIG. 22A is an isometric of a seventeenth embodiment of the distractiondevice of the present invention.

FIG. 22B is an enlarged fragmentary isometric of the distal tip of thedevice of FIG. 22A in a closed position.

FIG. 22C is a fragmentary isometric similar to FIG. 22B with the tip inan expanded position.

FIG. 22D is a diagrammatic vertical section showing the device in theexpanded condition of FIG. 22C inserted into a facet joint.

FIG. 23A is an isometric of an eighteenth embodiment of the distractiondevice in accordance with the present invention.

FIG. 23B is an enlarged fragmentary isometric showing the tip of thedevice of FIG. 23A in a closed position.

FIG. 23C is a fragmentary isometric similar to FIG. 23B with the tip inan expanded position.

FIG. 23D is a diagrammatic vertical section showing the device in theexpanded position of FIG. 23C inserted into a facet joint.

FIG. 24A is an isometric of a nineteenth embodiment of the distractiondevice of the invention.

FIG. 24B is an enlarged fragmentary isometric of the tip of the deviceof FIG. 24A in a closed position.

FIG. 24C is a fragmentary isometric similar to FIG. 24B with the tipexpanded.

FIG. 24D is a diagrammatic vertical section showing the device in theexpanded position of FIG. 24C inserted into a facet joint.

FIG. 25A is an isometric of a first embodiment of an implant fordelivery with or in conjunction with a distraction device.

FIG. 25B is an isometric of a second embodiment of an implant.

FIG. 25C is an isometric of a third embodiment of an implant.

FIG. 25D is an isometric of a fourth embodiment of an implant.

FIG. 25E is an isometric of a fifth embodiment of an implant.

FIG. 25F is an isometric of a sixth embodiment of an implant.

FIG. 26A is an isometric of a twentieth embodiment of the distractiondevice in accordance with the present invention.

FIG. 26B is a vertical section through the distal tip of the device ofFIG. 26A in a closed position.

FIG. 26C is a vertical section similar to FIG. 26A with the distal tipexpanded.

DETAILED DESCRIPTION OF THE INVENTION

Pursuant to the present invention, devices and techniques fordistracting and retaining a facet joint in a distracted and forwardlytranslated condition are disclosed. Prior to distracting the facetjoint, the joint, which can be difficult to access, can be accessedpursuant, for example, to the method and apparatus disclosed in U.S.Non-provisional application Ser. No. 12/350,609, filed Jan. 8, 2009,which is commonly owned with the present application and herebyincorporated by reference. Pursuant to the disclosure in thatapplication, the access system is comprised of one or more cannulas madeof steel, titanium, or plastic. The initial facet joint access cannulacan have a sharp spatula tip on the distal end. The spatula tip can havea flat configuration to enable access into the flat facet joint. Oncethe spatula tip achieves access into the generally flatly oriented facetjoint, subsequent stylets and working instruments can be passed downthis access channel to complete a distraction procedure. The distractionprocedure can be accomplished with devices and techniques to bedescribed hereafter.

The percutaneous distraction mechanism can be introduced down theworking cannula of the above-identified access system. The mechanism canbe part of a delivery tool that would allow the surgeon to generatedistraction by applying energy to a handle of the delivery tool for thedistraction mechanism positioned at the distal end of the tool. Thehandle of the delivery tool can be configured in any number of waysincluding but not limited to the following:

a) Trigger grip—index finger activates distraction by pulling thetrigger to apply energy to the distraction mechanism.

b) Scissor grip—index and middle fingers meet and separate to applyenergy to the distraction mechanism.

c) Thumb wheel or slide—thumb rolls a wheel or slides a slide thatprogressively applies more energy to the distraction mechanism.

d) Thumb cushion rod—thumb plunges a stylet down the working cannula toapply energy to the distraction mechanism.

e) Stylet screwdriver—stylet is threaded down the working cannula intothe distraction mechanism applying increasingly more energy to thedistraction mechanism as the stylet screwdriver advances.

f) Mallet based handle—a stylet with a flat malleable surface isinserted for the purposes of receiving and dispersing mallet energy andapplying it to the distraction mechanism.

g) Thumb button—a button on the proximal end of the handle is pushedwhich creates one of a number of mechanical systems to apply energy tothe distraction mechanism. Those mechanical systems could include butare not limited to:

-   -   i) hydraulic pressure generation;    -   ii) mechanical drill;    -   iii) level system; or    -   iv) elastic bands with “rope and pulley” mechanism.

h) Wedge firestarter—triangular wedge located at the proximal end of thetool is flattened to generate energy to apply to the distractionmechanism.

i) Foot or hand pump—feet or hands of surgeon used to press the systemto create energy to be applied to the distraction mechanism.

Referring to FIGS. 1-5, a description relating to any and/or all of thedelivery tools and associated distraction mechanisms and implantsdisclosed herein is presented. Referring first to FIG. 1, a portion of aspinal column 30 is shown having facets 32 on vertebrae 34 and withfacet joints 36 between adjacent facets 32 of the vertebrae 34. Thespinal cord 38, of course, passes vertically through the alignedvertebrae 34 with peripheral nerves 40 passing from the spinal cord 38outwardly through the spinal column 30 through foraminal openings 42 topredestined locations in the human body. When facet joints 36 becomenarrowed, usually from disc degeneration, the foraminal openings 42 arereduced in size pinching the nerve and causing pain to the individual.

Pursuant to the present invention, the facet joint 36, for example asshown in FIG. 2, can be accessed using a system, for example, of thetype described in the aforenoted U.S. Non-provisional patent applicationSer. Nos. 11/618,619 and 12/350,609, and after gaining access to thefacet joint 36, a delivery tool 46 shown by way of example in FIG. 3,can have its distal end inserted into the facet joint 36 and byexpanding a distraction mechanism at the distal tip of the tool 46, thefacet joint 36 can be distracted or enlarged. The distraction mechanismitself can be detachable from the tool 46 and left in the facet joint 36as an implant or a separate implant can be inserted with the deliverytool 46 or otherwise once the joint 36 has been distracted. Accordingly,it is noted that while the tools herein are referred to as deliverytools because they may be used to deliver a distraction mechanism, thedistraction mechanism may or may not be the resulting implant. FIG. 4shows from a lateral location an implant 48 positioned in a facet joint36 which holds the joint 36 in a distracted condition, while FIG. 5 is aplan view showing implants in position on facets 32 of a vertebra 34.

A first embodiment of a delivery tool 59 in accordance with the presentinvention is shown in FIGS. 6A-6C. It will there be seen, pursuant tothe above description with any and/or all of the embodiments of thepresent invention to be disclosed hereafter, a delivery tool can beinserted down the working cannula, for example of the access systemdescribed previously, which can be docked in a facet joint 36. Thedistal end of the delivery tool can be positioned at the anterior aspectof the joint 36 and the surgeon can apply energy to the delivery tool tocreate separation and distraction of the facet joint 36. The separationcan occur in both the vertical and horizontal planes of the joint 36resulting in vertical distraction and forward/anterior translation ofthe superior vertebrae relative to the inferior vertebrae. The facetjoint distraction and forward translation can cause an increase inforaminal area and thus reduce nerve root compression and associatedsymptoms.

Referring to the first embodiment of the invention shown in FIGS. 6A-6C,a delivery tool 59 can include a handle 57, a distraction cannula 52,and a distraction mechanism 50. The handle portion 57 can include any ofthe energy delivering handles described above. The handle 57 can beconnected to the cannula 52 and the distraction mechanism 50 positionedwithin the cannula 52. The handle 57 can be configured to actuate thedistraction mechanism 50.

The distraction mechanism 50 can be positioned at the tip of thedelivery tool 59 and can include a band 54 of a somewhat rigid materialthat can be flexed so as to expand and become tall and generallyflattened as it exits a rectangular opening 56 in the wall 58 of thedistraction mechanism 50. The proximal end of the band 54 can bemoveable and the distal end can be restrained. The rectangular opening56, and thus the corresponding protruding band 54 can be smaller inlength and width than the dimensions of the facet joint 36 beingtreated. The band 54 can be made of titanium, carbon, PEEK, nitinol,allograft, polymer, or plastic. Other elastic materials can be used.

In use, the handle 57 can be actuated thereby advancing the band 54. Theforce on the band 54 together with the restrained distal end of the band54 can cause the band 54 to change its shape and configuration. That is,the compression developed in the band 54 can cause it to buckle out ofplane and bow upwardly through the opening 56 and allow it to flattenout or conform to surface profile of the articular surface of thesuperior facet. While the band 54 may be sufficiently flexible to bowunder compression, it may be sufficiently rigid to apply energy or forceto the contacted articular surface. This applied force can result in thedistraction and forward translation of the joint 36.

In one embodiment, the distraction mechanism 50, once expanded, can beseparated from the cannula 52 and remain in place as an implant toretain the expanded condition of the facet joint 36. This may occur byway of a circumferential perforation between the cannula 52 and thedistraction mechanism 50 just proximal to the opening 56. A releaselatch can also be provided between the cannula 52 and the distractionmechanism 50. Accordingly, the cannula 52 can be released from thedistraction mechanism 50 and handle 57 and cannula 52 can be removedleaving the distraction mechanism 50 behind. In an alternativeembodiment, a separate implant of the types to be described hereafter inother embodiments of the invention could be positioned in the distractedfacet joint 36 before the distraction device was removed.

A second embodiment of the invention is shown in FIGS. 7A-7C. A handle67 and cannula 62 can be provided as described previously. In thisembodiment, a distraction mechanism 60 in the form of a collapsible boxcan be positioned on the distal end of the delivery tool 69. Thedistraction mechanism 60 can include upper 66 and lower 64 walls as wellas end walls 68 with the walls 64, 66, 68 being pivotally connected sothe device is movable between a flattened position as shown in FIG. 7Bto an expanded position as shown in FIG. 7A. A locking mechanism canalso be provided such as a cross-brace or other device for maintainingthe mechanism 60 in an expanded position once expanded.

Fixation mechanisms 70 can be provided on the exterior surface of bothupper 64 and lower 66 walls. These fixation mechanisms 70 can be in theform of 1) Aggressive shark teeth, 2) Cleats, and/or 3) Roughened pores.The aggressive shark teeth (as shown in FIG. 7A) can have a directionalorientation positioned to achieve optimal fixation relative to thenatural biomechanics of various sections of the spine. The teeth can belong enough to gain purchase in the cortical bone of the facet surfaces.The cleats can have a less aggressive profile than the shark teeth butstill allow for directional orientation for the same reasons describedabove. These cleats can also be capable of anchoring in the hardcortical bone of the facet surface. The roughened pores be positioned onthe surface and can be adapted to prevent free sliding of the facetjoint 36. These surfaces can be roughened and coated with FDA masterfile approved resurfacing chemicals that create friction and preventdevice migration.

The collapsible box can be made of titanium, steel, carbon, PEEK,nitinol, polymer, or plastic. As with the embodiment described above,the collapsible box system can be configured to detach for permanentimplantation or can be used to retain distraction of the joint 36 whilean auxiliary implant or gel is positioned in the distracted joint 36.

In use, the collapsible box can be inserted through the cannula of anaccess system as described previously to position the collapsible boxwithin the facet joint 36. The box can be actuated with the handle 67 ofthe tool causing the box to transition from a collapsed or flatparallelogram configuration to an expanded rectangular configuration. Asis probably best appreciated by reference to FIG. 7A, the collapsiblebox can be moved between its collapsed and expanded conditions byactuating the handle 67, which can pull or push on an upper flexible butsomewhat rigid strip 72 connected to the upper wall 64 while a lowersimilar strip 74 connected to the lower wall 66 holds the lower wall 66in a fixed position. The expansion can create separation of the facetjoint 36 in both the vertical and horizontal planes. As the collapsiblebox expands and causes distraction and translation, the fixationmechanisms 70 engage the facet surfaces securing the structure andallowing for controlled distraction and translation of the facet joint36.

A third embodiment of a delivery tool 79 in accordance with theinvention is shown in FIGS. 8A-8C and can be seen to be similar to thatof the second embodiment of FIGS. 7A-7C. In this embodiment, adistraction mechanism 76 in the form of a collapsible box is againutilized but the bottom surface of the lower wall 78 of the box hasfixation mechanisms 80 for engaging the lower facet to hold the lowerwall 78 of the box in a fixed position while the upper wall of the boxwith no such teeth is shifted relative thereto with a pair of rigid butsomewhat flexible strips 84 that can be extended or retracted with theinsertion handle 77 to expand or flatten the collapsible box,respectively.

A fourth embodiment of a delivery tool 89 in accordance with the presentinvention is shown in FIGS. 9A-9C. In this embodiment of the invention,the distraction mechanism 88 can have a diamond-shaped or oblongdistraction head 90 made from a somewhat rigid but flexible band orstrip of material. The mechanism 88 can include an actuator in the formof an elongate member 92 extending longitudinally there through that isadapted to draw the opposing ends 94, 96 of the distraction head 90together. The elongate member 92 can be a threaded member adapted todraw the ends 94, 96 of the head 90 together by interaction with afemale member 91. The interaction can be via a screw action with afemale threaded member as shown. Alternatively, the elongate member 92can be a toothed member adapted to draw the ends 94, 96 of the head 90together via a ratcheting action with a female ratchet member similar tothat of a cable tie. In either case, the elongate member 92 can extendthrough the head 90 of the distraction mechanism 88 and can include astop or flange 93 on a distal end preventing the head 90 from advancingbeyond the distal end of the elongate member 92. The female member 91can be positioned on the elongate member 92 just proximal to the head90. Advancing the female member 91 along the elongate member 92 viascrewing action or sliding ratcheting action can compress the head 90between the female member 91 and the flange 93 thereby causing the head90 to expand as shown when comparing FIG. 9B to 9C.

It is noted that several alternative configurations and relationships ofthe elongate member 92 with a female member 91 can be provided. That is,for example, one end of the head 90 can form the female member 91 suchthat actuation of the elongate member 92 causes the end of the head 90with the female member 91 to walk along the elongate member 92 therebydrawing the ends 94, 96 of the head together. Other configurations andrelationships can be provided and are within the scope of the presentinvention.

It is also noted that FIGS. 9A-9C depict a female member 91 in the formof a nut that is threadable over an elongate member 92 in the form of abolt. Accordingly, the cannula 86 of the delivery tool 89 includes adistal tip in the form of a nut driver. Those of skill in the art willunderstand and appreciate that alternative engagements between thecannula 86 and the female member 91 or the elongate member 92 can beprovided. That is, depending on the configuration, actuation mayrequired that the female member 91 be rotated or advanced and in otherconfigurations, the elongate member 92 may need to be rotated, advanced,or even withdrawn. In some embodiments, the engagement between thecannula 86 and the female member 91 or elongate member 92 can be, forexample, a straight screw driver tip, an allen wrench type tip, or otherengaging shapes.

The head 90 of the distraction mechanism 88 can be made out of titanium,steel, carbon, PEEK, nitinol, or plastic. Other materials can be used.The distraction mechanism 88 can be configured to detach from thedelivery tool 89 as shown so that it becomes a permanent implant.Alternatively, the distraction mechanism 88 can be used only fordistraction purposes so that a separate implant can be positioned in thefacet joint 36 to retain the distraction while the distraction mechanism88 is removed. In this embodiment, the cannula 86 can include a morepermanent connection to the female member 91 or elongate member 92 incontrast to that depicted in FIGS. 7B and 7C.

In use, energy can be applied to the flattened diamond or oblong head 90via the handle 87 and cannula 86 assembly. The energy can cause theopposing ends 94, 96 of the head 90 to draw together and the head 90 canexpand resulting in an increased height in the head 90. The expansion ofthe head 90 can cause the surfaces of the head 90 to engage with thefacet surfaces. As the head 90 expands against the facet surfaces, thejoint 36 can separate in both the horizontal and vertical planes. Thisseparation can lead to distraction and forward translation of the facetjoint 36. Moreover, the flexible nature of the head 90, whilesufficiently rigid to cause separation of the joint 36, may also conformto the contour of the articular surfaces of the facet joint 36 therebydistributing the compressive load from the joint 36 more evenly over thesurface interacting with the distraction mechanism 88. This shapeconformance can also function to resists withdrawal or dislodgement ofthe implant. Additionally, while not shown, the head 90 of the devicecan include fixation mechanisms along the surface of the head 90 adaptedto engage the articular surfaces of the facet joint 36.

A fifth embodiment of the distraction mechanism of the present inventionis shown in FIGS. 10A-10D. In this embodiment, pairs of pivotal teeth100 can be mounted on a common base or central core 95. The teeth 100can be pivotal between a folded or retracted position as shown in FIG.10C or the teeth 100 can be pivoted outwardly. Each pair of teeth 100may be pivotal independent of the other teeth 100. However, as in theembodiment shown, the teeth 100 may overlap in the retracted positionsuch that when underlying teeth 100 are pivoted outwardly the overlyingteeth 100 are naturally lifted. The retracted position can provide forinsertion of the mechanism 98 into a facet joint 36 and the outwardlypivoted position can serve to distract the joint 36.

The distraction mechanism 98 can also include an actuation device in theform of an elongate member 101 adapted to be advanced into the base orcentral core, where advancing the elongate member 101 can serve toactuate the teeth 100 and pivot them outwardly. As shown, the elongatemember 101 can be a threaded member and the central core 95 can includethread slots positioned below the position of the retracted teeth 100and relatively close to the pivot point of the teeth 100. Accordingly,when threaded member is advanced into central core 95, the threads fromthe threaded member can protrude through the thread slots and can engagethe teeth 100 relatively close to the pivot point of the teeth 100. Theprotruding thread can thus distract the teeth 100 and pivot themoutward. As the threaded member is continually advanced, additionalteeth 100 can be distracted thereby distracting the facet joint 36. Theclose proximity of the protruding thread to the pivot point of the teeth100 can function to minimize the distance that the thread must protrudeto suitably distract the associated teeth 100.

In an alternative embodiment, the elongate member 101 may be alongitudinal shaft with radiused fins positioned along two lateral sidesof the shaft. Each pair of fins can be positioned to correspond to eachpair of teeth 100 and the fins can be positioned longitudinally alongthe elongate member 101 so as to be in close proximity to the pivotpoint of a respective pair of teeth 100. The elongate member 101 can berotated causing the fins to pass beneath the teeth 100 near theirrespective pivot points and cause the teeth 100 to simultaneously pivotoutward.

In still another embodiment, the elongate member 101 can be in the formof plunger type actuation device. In this embodiment, the teeth 100 mayextend through the base or central core 95 via a slit in the base orcentral core 95. The teeth 100 can further extend to and be pivotallyconnected to the elongate member 101 passing through the central core95. Accordingly, advancing the elongate member 101 forward or distallycan cause the teeth 100 to retract due to decreasing the angle of thepivot point of the elongate member 101 relative to the slit throughwhich it passes. Withdrawing the elongate member 101, on the other hand,can cause the teeth 100 to pivot outwardly simultaneously thusfunctioning to distract the joint 36. In this embodiment, the elongatemember 101 can threadably engage the inside of the central core 95 toallow for controlled advancement and withdrawal of the elongate member101 or the elongate member 101 can be slidably received in the centralcore 95.

Any or all of the above described elongate members 101 can include anengagement feature at a proximal end for engagement by the cannula 105or device positioned within the cannula 105. The engagement feature canbe adapted to provide for transferring rotational, advancing, orwithdrawing forces. As shown, the engagement feature can include astraight screw driver receiving slot 103. The engagement feature can bean allen type connection or a hex head for receiving a nut drivingdevice, or a square head for receiving a square drive device. Those ofskill in the art will understand and appreciate that several engagementfeatures are available and are within the scope of the invention.

When energy is applied to the handle 97 of the tool 99, the teeth 100 ofeach pair can change their orientation or expand to achieve a suitableangle relative to the central core 95. In some embodiments this anglecan range from approximately 10° to approximately 90°. In otherembodiments, this angle can be approximately 45°. In this embodiment, inits fully expanded state, the mechanism 98 can take on the appearance ofa Christmas tree.

In use, the mechanism 98 can be inserted into the facet joint 36 in aflattened, collapsed state. Distraction energy can be applied to thehandle 97 causing the mechanism 98 to expand which causes the multipleteeth 100 to engage both the top and bottom facet surfaces of the joint36. As the mechanism 98 is expanded to achieve increasingly largerdimensions, the facet joint 36 surfaces can separate. This separation inboth the vertical and horizontal planes of the facet joint 36 can causedistraction and translation of the facet joint 36.

A sixth embodiment of a tool 109 of the present invention is shown inFIGS. 11A-11C. In this embodiment, the distraction mechanism 102 at thedistal end of the tool 109 can have a relatively flat and ovular head110 with a beveled tip 106 to facilitate insertion into the facet joint36. The mechanism 102 can have opposing relatively flat surfaces wherethe edges 112 interconnecting the surfaces are rounded along the lateraland medial edges of the mechanism 102. The distraction mechanism 102 canbe connected to the distal end of the cannula 107 with a rotationallyresistive connection such that rotation of the cannula 107 causesrotation of the mechanism 102.

In use, distraction energy can be applied to the handle 108 of thedeliver tool 109 to cause rotation of the distraction mechanism 102. Asthe flat head 110 of the mechanism 102 rotates, the articular surfacesof the facets can be forced apart due to a height of the mechanism(through the width of the head 110) being greater than its flatteneddimension. The increased height achieved from rotation of the mechanism102 can cause the flat, round surfaces of the mechanism 102 to engagethe facet surfaces and separate them. This rotational distraction canresult in vertical and horizontal separation of the facet joints 36achieving distraction and forward translation of the joint 36.

The distraction mechanism 102 can be mounted on the distal end of thedelivery tool 109 so that it can be removed from the delivery tool 109if desired to remain as an implant to retain the distraction of thejoint 36 or can be retained in position until an auxiliary implant ispositioned in the joint 36 and then removed with the delivery tool 109.

A seventh embodiment of the present invention is shown in FIGS. 12A-12D.This embodiment is similar to that of the sixth embodiment in that themechanism 104 is rotatable to achieve distraction of the joint 36, butrather than possibly serving as a mechanical implant, as is possiblewith the sixth embodiment, the mechanism 104 can be used to inject afluid such as a hydrogel, PMMA bone cement, BMP, silicone, or the like,into the facet joint 36. The distraction mechanism 104 can be mounted onthe distal end of a delivery tool 114, which uses a thumb slide 118 forapplying energy to the mechanism 104. The distraction mechanism 104comprises a somewhat flattened and rigid blade 120 that is slightlyS-shaped in cross-section and is hollow with the hollow interior of themechanism 104 communicating with lateral ports 122 in notches 124 formedin the side edges of the blade 120. When the mechanism 104 is insertedinto a facet joint 36, it is inserted with its relative flat dimensionoriented generally parallel to the articular surfaces of the joint 36.To obtain distraction, the mechanism 104 can be rotated with thedelivery tool 119, which can cause the joint 36 to distract. Once thejoint 36 has been distracted, a gel or other suitable fluid can beemitted through manipulation of the thumb slide 118 on the delivery tool119 so that the gel is forced through the hollow interior of the deviceand out the injection ports 122 to fill the facet joint 36 to thedesired level. The distraction mechanism 104 can then be withdrawn withthe gel serving as an implant to retain the distracted joint 36 at thedesired separation.

As with the rest of the embodiments of the invention described herein,in some versions of the embodiment depicted in FIGS. 12A-12D, the tool119 may include a central delivery lumen through which an implant may bedelivered, for example, via a plunger or push rod, to the distractedfacet or joint space. In other versions of the embodiment depicted inFIGS. 12A-12D, another delivery tool may be employed once thedistraction mechanism 104 has distracted the joint 36.

An eighth embodiment of the invention is shown in FIGS. 13A-13D. In thisembodiment, the distraction mechanism 126 can have a generally hollowelongated body 130. In some embodiments, the body 130 may be relativelycone-shaped. The thickness of the body 130 can be small enough so it canbe initially inserted a short distance into a relatively flat andcollapsed facet joint 36. The body 130 can include facet engagingfeatures 132 including diametrically opposed deployable keels (FIG.13B), thread slots (FIGS. 13A and 13D), or deployable teeth (FIGS. 13E,13F, and 13H). The keels can have a retracted position wherein they liewithin the confines of the body 130, but, when activated as indicatedwith the arrows in FIG. 13B, extend in a tapered manner away from theouter surface of the body 130. The thread slots shown in FIG. 13A can beadapted to receive treads from an actuator that can be advanced throughthe body 130 to distract the facet joint 36. The threads of the actuatorcan gain purchase in the articular surfaces of the facet by protrudingthrough the thread slots of the body 130. The deployable teeth, like thekeels, can have a retracted position wherein they lie within theconfines of the body 130, but, when activated, extend through openingsin the body 130 to engage the articular surfaces of the facet joint.

The distraction mechanism 126 can include an actuator as shown in theform of an elongate member 134. The elongate member 134 can be athreaded member or a toothed ratchet type member adapted to be insertedthrough the hollow core of the body 130. As shown in FIGS. 13A and 13B,the elongate member 134 can be a screw or bolt type member adapted tothreadably engage the body 130. The elongate member 134 can be actuatedand advanced via distraction energy applied to the tool 129 via a handle128 as previously described. In the case of a body 130 having keels, theadvancing elongate member 134 can result in the expanding keels engagingthe facet surfaces of the joint 36 causing separation of the joint 36 asincreasingly more distraction energy is applied resulting inprogressively more deployment and height of the device with the keelsalso providing fixation to the facet surfaces. In the case of threadedslots, the advancement of the elongate member 134 can expand or stretchthe body 130 or merely advance through the body 130. As the threads ofthe elongate member 134 engage the threaded slots, the threads canprotrude through the slots and cut into or otherwise engage thearticular surfaces of the facet joint 36. In the case of deployableteeth, the advancing elongate member 134 can force the teeth throughopenings in the body 130 thereby causing them to engage the facetsurfaces of the joint 36 allowing for secured positioning of theimplant.

As shown, the elongate member 134 can include an engagement feature 135for receiving a corresponding engagement feature from the cannula 127 ofthe delivery tool. As shown the engagement feature 135 of the elongatemember can be adapted to receive a straight screw driver tip. Otherrotating and/or driving engagements can be provided.

A ninth embodiment of the invention is shown in FIGS. 14A-14C. In thisembodiment, the distraction mechanism 138 may include one or more leafblades 142 with tapered tips 144. The blades 142 may extendlongitudinally from a delivery tool cannula 137 and may be stackedrelative to one another. The blades 142 may be actuatable independent ofone another and may be actuatable in consecutive order.

The blades 142 can be made of steel, titanium, PEEK, carbon, or nitinol.Other materials can be used. The blades 142 can be configured astemporary distraction shims or permanent detachable implants which canbe left in the distracted joint 36. If the stacked blades 142 areconfigured for detachment and permanent implantation, they can includeone or more of the previously described fixation mechanisms.Additionally, the blades 142 can include relative motion restraintsadapted to prevent relative slippage from occurring between blades 142.These restraints can include detent recesses and protrusions or otherrestraints.

The distraction achieved with this system can occur by advancing theblades 142 one at a time into the facet joint 36 so that as anincreasing thickness or height of the stack of blades 142 is insertedinto the joint 36, distraction is achieved. The number of blades 142extended into the joint 36 can be increased until the desireddistraction of the joint 36 is achieved.

The handle 140 of the present embodiment can include any of the handlespreviously described. However, as shown in FIGS. 14B and 14C, the handle140 can include a rotating dial type handle 140 such that rotation ofthe dial relative to the handle 140 causes actuation of the blades 142.This can occur through an internal screw system that can convert radialmotion to longitudinal motion. Additionally, the proximal ends of theblades can be initially staggered such that an internally advancing rodcan first engage and advance the bottom blade, and then the next blade,and the next blade, and so on. Accommodations can also be made to avoidcontinued advancement of a given blade 142 once it enters the joint.Accordingly, incremental rotation of the dial can cause incrementaladvancement of the internal rod and thus consecutive advancement ofblades 142.

The dial can include measurements corresponding to the thickness of eachof the advancing blades 142 and can thus display to the user, the totaldistraction being provided by the blades 142. That is, rotation of thedial can advance a first blade 142 into the joint 36 and the indicationon the dial can reflect the thickness of the first blade 142 and thusthe resulting distraction. Upon further rotation of the dial, additionalblades 142 can be advanced into the joint 36 and the indication on thedial can reflect the cumulative thickness of the first blade 142 and theadditional blades thereby reflecting the total distraction.

Accordingly, the present embodiment can be used to distract a facetjoint 36 as described and can also be used as an implant. However, thetool 139 can also be used to calibrate or prepare for a distractionprocedure by assisting a user in determining the appropriate amount ofdistraction. In one embodiment, the tool 139 described can be used toobtain intra operative feedback from a patient. The tool 139 can be useto incrementally distract a joint 36 to determine how much distractionis necessary to alleviate patient symptoms. Based on feedback from thepatient, an appropriately sized implant can be selected for insertioninto the facet joint 36. The current embodiment can then be used tomaintain the facet joint 36 in a distracted condition for placement ofthe implant or other devices can be used to place the implant.

In one version of the embodiment depicted in FIGS. 14A-14C, each of theblades 142 of the mechanism 138 may have a longitudinally extending slot(not shown) defined therein and positionally corresponding with theslots of the adjacent blades 142 to define an overall slot (not shown)through which an implant may be delivered, for example, via a plunger orpush rod, to the distracted facet or joint 36 space. In other versionsof the embodiment depicted in FIGS. 14A-14C, another delivery device maybe employed once the mechanism 138 is used to distract the facet joint36.

Referring to FIGS. 15A-15C, a tenth embodiment of a distractionmechanism 146 of the invention is illustrated. In this embodiment, arotatable loop 148 of rectangular configuration made of a rigid materialcan be pivotally mounted on the distal end of the delivery tool 149 andcan carry within the loop 148 an implant of the type disclosed in theprior embodiments, or of types to be disclosed hereafter, which can bedeposited or left in a distracted joint 36. The loop 1478 can haveelongated side legs 154 and relatively short end legs 156 with fixationmechanisms 158 such as teeth on both surfaces of the short legs 156 ofthe loop 148. The pivotal mount between the loop 148 and the delivertool 149 can be positioned approximately midway along the length of theside legs 154.

Distraction energy can be applied to the rigid loop 148 from the handleend of the delivery tool 149 causing the trailing end of the loop 148 torotate forwardly, as illustrated with the arrows in FIG. 15A (posteriorto anterior). Together with the teeth on the surface of the loop 148,the loop 148 can engage the facet surfaces to separate the joint 36. Theforward rotation of the loop 148 can distract the joint 36 and also pushthe superior facet slightly forward in translation relative to theinferior facet.

When the desired distraction and translation of the facet joint 36 isachieved, the tool 149 can deposit the implant, which is carried withinthe loop 148. The implant can be carried within a hollow inside thecannula 147, for example. The implant can be introduced into thedistracted joint 36 and deposited therein prior to the mechanism 146being removed.

An eleventh embodiment of a distraction mechanism 160 of the presentinvention is shown in FIGS. 16A-16C. The distraction mechanism 160 caninclude an expandable receiving portion having upper 164 and lower 166generally planar elements which are connected at an end with a livinghinge so that the mechanism 160 can be flattened for insertion into afacet joint 36. As shown, the upper and lower generally planar elements164, 166 can be relatively triangularly shaped or trapezoidally shapedwith the living hinge being positioned near the narrower end of therespective shapes. Other shapes, such as, for example, rectangular, ofthe planar elements 164, 166 can be used. The outer surface of theplanar elements 164, 166 can include tapered keels as fixationmechanisms 170 which assist in gripping the superior and inferior facetsurfaces. The keels can be provided along the edges of the planarsurfaces 164, 166 as shown or they can be provided more centrally to theplanar surfaces 164, 166. The outer surface can also include threadedslots as fixation mechanisms 170 for receiving threads from an actuatorbeing advanced into the receiving portion. The outer surface can alsoinclude teeth as fixation mechanisms 170 adapted to engage the facetsurfaces.

An actuation device 172 can be included, as shown in FIG. 16A, and cantake the form of a wedge, an elongated member, or block-type member. Inthe case of a wedge actuation device, the wedge can be advanced into thereceiving portion between the planar members 164, 166 forcing the planarmembers 164, 166 apart and distracting the joint 36, as shown in FIG.16B. The fixation mechanisms 170 on the surface of the planar members164, 166 can engage the facet surfaces thereby resisting any tendencyfor the mechanism 160 to back out of the joint 36.

In the case of an elongate member, the elongate member can be advancedbetween the planar members 164, 166 forcing the planar members 164, 166apart and distracting the joint 36. As shown, the elongate member mayinclude a tapered tip to initiate the advancement. In addition, theelongate member can include threads to facilitate advancement into thereceiving portion. Moreover, where threaded slots are provided on theplanar members 164, 166, the threads of the elongate member can engagethe threaded slots and protrude through the threaded slots. Accordingly,the threads can cut into or otherwise gain purchase in the facetsurfaces to prevent any back out tendency of the mechanism 160.

In the case of a block-type actuation device, the block can be advancedbetween the planar members 164, 166 forcing the planar members 164, 166apart and distracting the joint 36. The block can include a taper (notshown) at a distal end for initially engaging and separating the planarmembers 164, 166. Alternatively or additionally, a portion of the planarmembers 164, 166 may extend outside the facet joint 36 and may be priedapart for initial insertion of the block after which the forcedadvancement of the block can cause separation of the facet allowing theblock to be fully inserted into the receiving portion and into the facetjoint 36. Where the receiving portion includes teeth and/or keels, thesefixation mechanisms 170 can be forced into the facet surfaces gainingpurchase therein.

The receiving portion of the mechanism 160 can be carried on the distalend of a delivery tool 159 and can be inserted into the facet joint 36in a collapsed state. One of the actuation devices 172 described canthen be inserted into the receiving portion from its open trailing endto expand the receiving portion by separating the planar elements 164,166 until the desired distraction of the joint 36 is achieved. Thisseparation can lead to distraction and forward translation of the facetjoint 36.

As shown in FIGS. 16A and 16B, the receiving portion can conform to theshape of the articular surfaces of the facet joint 36 as described withrespect to the embodiment shown in FIG. 9. As such, the distractionmechanism 160 can distribute the compressive load from the joint 36 moreevenly over the surface interacting with the distraction mechanism 160.This shape conformance can also function to resists withdrawal ordislodgement of the mechanism 160 or implant. It is further noted thatthis shape conformance can be multidirectional and where the keels arepositioned along the edges of the planar elements 164, 166, the keelsmay facilitate folding or bending of the planar surface 164, 166 aroundthe actuation device 172 allowing a fixation feature more central to theplanar surface 164, 166 (e.g., teeth) to also engage the facet surface.

The distraction mechanism 160 in this embodiment can be removably orpermanently mounted on the distal end of an insertion tool 159 so it canbe removed from the insertion tool 159 and left in the distracted joint36 as a permanent implant or removed from the distracted joint 36 afteran auxiliary implant is positioned therein.

With reference to FIGS. 17A-17C, a twelfth embodiment of the inventionis illustrated. As best appreciated by reference to FIGS. 17A and 17B,the distraction mechanism 174 can be configured like a medical capsule(FIG. 17B) so as to be cylindrical in configuration with rounded leadingand trailing ends 176. The mechanism 174 can be formed from twogenerally ovular or tear-drop shaped components with an upper component182 having fixation mechanisms 180 on its upper surface and the lowercomponent 186 having fixation mechanisms 180 on its lower surface. Thecomponents can be slidably related along a diagonal plane 188 ofseparation.

In use, the mechanism 174 can be inserted into the facet joint 36 with adelivery tool 169 having the mechanism 174 positioned on its distal end.As the mechanism 174 is advanced, the fixation elements 184 can grip theopposing facet surfaces causing the tear-drop components 182, 186 totranslate along the diagonal plane 188 in one direction or the other. Inone direction, of course, the implant becomes longer with a maximumheight of the diameter of the capsule as seen in FIG. 17B while in anopposite direction the components 182, 186 slidably converge along thediagonal plane 188 so that the implant is cammed into a taller orthicker dimension causing more distraction of the joint 36. Themechanism 174 can have any number or type of fixation mechanisms 180 onthe top and bottom surfaces to prevent migration.

The opposing surfaces along the diagonal plane 188 can be somewhatsmooth to prevent excessive friction while facilitating small amounts ofmotion along the diagonal plane 188 once the mechanism 174 ispermanently fixed against the superior and inferior facet surfaces.

The mechanism 174 can be made of steel, titanium, PEEK, silicone,plastic, polymer, or nitinol. The mechanism 174 can be detachable tofacilitate permanent implantation, but, as with the other embodiments,can be removed once an auxiliary implant is positioned upon distractionof the joint 36 with the mechanism 174.

A thirteenth embodiment of a distraction mechanism 192 of the inventionis shown in FIGS. 18A and 18B. The mechanism 192 of this embodiment caninclude a polyethylene balloon 194 mounted at the distal end of adelivery tool. The distal end of the delivery tool within the balloon194 can include a large conduit 198 with two separated enclosed vessels200, 202 and an output port 204 on the bottom of the devicecommunicating with an inlet vessel 200 and an intake port 206 on the topof the device communicating with a return vessel 202. Fluid can beinjected into the balloon 194 through the inlet vessel 200 and removedas desired through the return vessel 202 as shown by the directionalarrows in FIGS. 18A and 18B.

In use, the balloon 194 can be positioned within the facet joint 36 andthe balloon 194 can be inflated through the introduction of a contrastmedium fluid. Pressure within the balloon 194 can be developed throughfurther injection of fluid and thus the pressure can cause expansion ofthe balloon 194 structure. The balloon 194 expansion can causeseparation of the facet joint 36 resulting in distraction and forwardtranslation of the joint 36.

Once in place and expanded, as with other distraction mechanisms, themechanism 192 can be detached from the tool and used as an implant orthe mechanism 192 can be used to hold the distraction of the joint 36while another implant is placed. Where used as implant, the balloon 194can be filled with a bio-inert hydrogel once optimal distraction andtranslation of the facet joint 36 is achieved. Also, a sealing valve atthe proximal aspect of the balloon 194 can be provided to preventleaking of the hydrogel. Alternatively or additionally, the balloon 194can be inflated with a fast-curing silicone when used as a permanentimplant.

In another embodiment of the balloon 194 (not shown), the balloon 194can be forked shaped having two legs and a recess therebetween in whicha permanent implant of any of the types previously described, or to belater described, can be positioned. In this configuration, the balloon194 can be inflated to achieve optimal distraction and translation, butcan be removed following the successful placement and fixation of thepermanent implant.

A fourteenth embodiment of a distraction mechanism 208 of the inventionis shown in FIGS. 19A and 19B and operates similarly to that of thethirteenth embodiment shown in FIGS. 18A and 18B. In the fourteenthembodiment, the main conduit 210 on the distal end of the delivery toolcan have a large enclosed channel 214 formed therein and a smallerenclosed channel 216 communicating with the large channel. The largechannel 214 can have an extended cylindrical vessel 218 protrudingbeyond the end of the main conduit and a rounded tip 220 with a lateraloutlet port 222 in a recess 224 formed in a side thereof. A balloon 226can be sealed to the large vessel 210 so that fluids emitted through theoutlet port 222 can fill and expand the balloon 226 to distract thefacet joint 36 as with the thirteenth embodiment, and the smallerenclosed channel 216 can be used to remove fluid from the balloon 226 asdesired.

A fifteenth embodiment of the distraction mechanism 228 of the inventionis shown in FIGS. 20A-20C. The mechanism 228 can again be mounted on thedistal end of a delivery tool with the mechanism 228 being a hollowcylinder 232 having tapered diametrically opposed protruding prongs 234at its leading end. The prongs 234 can define a recess 236 therebetweenand a hollow interior of the device can communicate with an injectionport 238 positioned between the prongs 234. The tapered prongs 234 canbe advanced into a facet joint 36 to spread the joint 36 apart to allowroom to inject fluid through the injection port 238. The injection port238 can be used for communicating a stylet to the facet joint 36 or forintroducing materials (including bone graft, BMP, OP1, silicone, PMMAbone cement, or hydrogel) and permanent implants to provide permanentdistraction and translation.

A sixteenth embodiment of the distraction mechanism 240 of the inventionis shown in FIGS. 21A-21C with this mechanism 240 again being mounted ona delivery tool. The mechanism 240 can include a pair of paralleltubular members 244 on lateral aspects of the distal tip of the deliverytool and a port 246 between the tubular members 244 communicating withthe hollow interior of the delivery tool. Each tubular member 244 canhave a relatively small leading end but become progressively larger asbigger tubes are telescoped over the smaller tubes. The larger tubes cancause increasing separation of the facet joint 36 resulting indistraction and forward translation. The port can facilitate theintroduction of subsequent instruments, stylets, materials (includingbone graft, BMP, OP1, silicone, PMMA bone cement, hydrogel) andpermanent implants to provide permanent distraction and translation.

A seventeenth embodiment of the invention is shown in FIGS. 22A-22D. Inthis embodiment, the distraction mechanism 248 is mounted on the tip ofa delivery tool having dual triggers 252, 254 for delivering energy tothe mechanism 248. The mechanism 248, as seen best in FIGS. 22B-22D, caninclude upper and lower arms 256, 258 having confronting flat faces withat least the upper arm being somewhat flexible while both arms aresubstantially rigid. The lower arm 258 can have a rearwardly andupwardly beveled leading tip 260 and a hollow interior in communicationwith side ports 262 on opposite sides of the arm 258. The upper arm 256can have a relatively flat main body which overlies in confrontingrelationship the lower arm 258 with the upper arm 256 having adownwardly and forwardly inclined leg 264 which conforms with the bevelof the lower arm 258. When the upper and lower arms 256, 258 arecollapsed, as shown in FIG. 22B, they lie in confronting contiguousrelationship with the leading edge of the upper arm 256 being close tothe elevation of the lower edge of the lower arm 258 so as to provide athin profile for insertion into a facet joint 36. One trigger on thedelivery tool can retract the upper arm 256 so that the inclined leg 264at the leading end thereof is cammed upwardly onto the top of the lowerarm 258 by the leading beveled edge 260 of the lower arm 258. Theretraction of the upper arm 256 can separate the upper arm 256 from thelower arm 258 as shown best in FIGS. 22C and 22D so that when they arepositioned within the facet joint 36, a distraction of the joint 36 canbe achieved. Once the joint 36 is distracted to the desired degree, theintroduction of instruments, stylets, materials (including bone graft,BMP, OP1, silicone, PMMA bone cement, hydrogel) or other permanentimplants of the type previously disclosed herein can be introducedthrough the side ports 262 with the second trigger to provide permanentdistraction and translation.

An eighteenth embodiment of the distraction mechanism of the inventionis shown in FIGS. 23A-23D. In this embodiment of the invention, thedistraction mechanism 266 can again be mounted on the distal end of adelivery tool having dual triggers 270, 272. The mechanism 266 can haveupper and lower blades 274, 276 each having forwardly tapered leadingends 278 so as to define a relatively thin leading tip resembling anelongated duckbill. The tip of the duckbill for the mechanism 266 can bethin enough or flat enough to access the facet joint 36. Once themechanism 266 is positioned within the facet joint 36, a distractionenergy can be applied to the mechanism 266 by pulling one trigger whichcauses an internal hollow cylinder 280 having a blunt leading end toadvance forwardly thereby separating the upper and lower blades 274,276. The separation can cause distraction of the facet joint 36 andlateral injection ports 282 can be provided on the internal cylinderthrough which instruments, stylets, materials (including bone graft,BMP, OP1, silicone, PMMA bone cement, or hydrogel) can be injected intothe facet joint 36 by the second trigger or other permanent implantscould be introduced to provide permanent distraction and translation.

A nineteenth embodiment of the invention is shown in FIGS. 24A-24D to besimilar to the eighteenth embodiment. In the nineteenth embodiment,again, upper and lower relatively rigid yet flexible blades 286, 288 canbe provided that in a closed position are contiguous and confrontingwith each other. Adjacent the leading end 298 of the blades 286, 288 thelower blade 288 can have a transverse cylindrical recess 290 formedtherein while the upper blade 286 can have a transverse cylindricalprotrusion 294 which seats in the recess 290 to permit the upper andlower blades 286, 288 to be contiguous in the closed position. Aninternal cylinder 294 having lateral ports 296 at its leading end can bepositioned between the blades 286, 288 and confined therebetween whenthe blades 286, 288 are closed so that tapered forward ends 298 of theblade can be inserted into the facet joint 36. By pulling the firsttrigger on the delivery tool, the upper blade 286 can be retractedrearwardly so that the cylindrical protrusion 292 is cammed by thecylindrical recess 290 to cause the upper blade 286 to elevate relativeto the lower blade 288 thereby distracting the facet joint 36. When thefacet joint 36 has been distracted, instruments, stylets, materials(including bone graft, BMP, OP1, silicone, PMMA bone cement, orhydrogel) can be injected into the facet joint 36 with the secondtrigger or other permanent implants of the types previously disclosedherein could be introduced to provide permanent distraction andtranslation.

FIGS. 25A-25F disclose various embodiments of permanent implants whichcan be inserted into a facet joint 36, for example, with a delivery toolof the type disclosed in the tenth embodiment or any other of theembodiments disclosed herein if such embodiments are supplemented withan integral delivery lumen and push rod configuration. Alternatively,the various embodiments of the above-described distraction mechanismscan be positioned in a facet joint 36 to retain the joint 36 in adistracted position, a translated position, or a combination distractedand translated position until a permanent implant can be positioned inthe distracted joint 36 separately via a separate delivery device ortool.

FIG. 25A shows a permanent implant 306 that is of wedge shape havingfixation mechanisms 308 on the top and bottom surfaces comprised ofteeth all directed in a common direction toward the trailing end of theimplant. The wedge shape can facilitate distraction that is both normalto the facet surfaces and parallel to the facet surfaces. In otherwords, the wedge shape can separate the facet surfaces from each otherin a direction that is perpendicular and a direction that is parallel tothe facet surfaces, thus both increasing the offset distance between thefacet surfaces and translating the facet surfaces relative to eachother. This combination of displacement can more fully open theforaminal spaces.

FIG. 25B shows another implant 310 having rounded leading and trailingends 312 and flat upper and lower parallel surfaces 314, again withteeth on both the upper and lower surfaces 314, which are inclinedrearwardly.

FIG. 25C discloses another wedge-shaped embodiment of a permanentimplant 318 where the upper surface 320 of the wedge has teeth 322directed forwardly and outwardly along opposite lateral edges at theleading edge of the wedge while the bottom surface 324 has similar teeth322 at the trailing end of the wedge directed rearwardly and outwardly.The oppositely oriented teeth 322 may enhance and help to maintain thetranslation displacement already provided by the wedge shape.

FIG. 25D shows a permanent implant 326 configured similarly to FIG. 25Bwith the trailing end 328 being squared off rather than rounded and withteeth 330 across the top of the leading end directed forwardly and teeth330 across the bottom and the trailing end directed rearwardly. Theoppositely oriented teeth 330 may provide a translation displacement.

FIG. 25E shows still another implant 332 of generally rectangularconfiguration but having a concave leading end 334 and a roundedtrailing end 336. The implant 332 has rearwardly directed fixationmechanisms 338 in the form of teeth along the upper surface on lateralsides and along the side walls.

Permanent implants can vary in geometry, material, and fixationmechanism. For example with respect to geometry a wedge shaped implantcan provide for a greater height of the posterior aspect of the implantrelative to the anterior aspect of the implant. The wedge can alsoprovide for uniform dimensions at the lateral and medial aspects of theimplant. The wedge shape may result in a translating vector force and aseparating vector force that results in both subluxation anddistraction, thereby increasing the foraminal space more fully asdiscussed in U.S. provisional patent application No. 61/059,723, filedJun. 6, 2008, and incorporated by reference herein in its entirety. Adouble wedged implant can provide greater height of the posterior aspectof the implant relative to the anterior aspect of the implant inaddition to greater height of the lateral aspect of the implant relativeto the medial aspect of the implant (see FIG. 25F). Other geometricalvariations can include a flat rectangular shape, an oval pill shape, aconcave superior surface, a concave inferior surface, a convex superiorsurface, a convex inferior surface, a convex anterior surface, a concaveanterior surface, a convex posterior surface, and a concave posteriorsurface.

With respect to materials, several materials can be provided includingsteel, PEEK, c

to achieve optimal fixation relative to the natural biomechanics ofvarious sections of the spine. The teeth can be long enough to gainpurchase in the cortical bone of the facet surfaces. Cleats can also beprovided that have a less aggressive profile than the shark teeth butstill allow for directional orientation for the same reasons describedabove. These cleats can also be capable of anchoring in the hardcortical bone of the facet surface. Additionally, a roughened poresurface can be provided to prevent free sliding of the implant withinthe facet joint 36. These surfaces can be roughened and coated withcommercially available resurface chemicals that would create frictionand prevent device migration.

Any or all of the implants can be adapted as fusion type implants ormotion preservation type devices. Implants with varying degrees ofmotion preservation can also be provided. In the case of a motionpreservation type implant, the implant can have fixation mechanisms onone side to enable both temporary and permanent fixation to one surfaceof the facet joint 36 while allowing the opposing facet surface to slidefreely across the surface of the implant. The facet joint 36 can be anaturally sliding joint 36 and a distraction implant with fixation ononly one side may accommodate the natural sliding of the facet. However,in some circumstances, a fusion type implant can be more suitable. Inthese circumstances the implant can include fixation mechanisms on bothsides of the of the implant.

FIGS. 26A-26C disclose a twentieth embodiment of a distraction mechanismof the invention which is somewhat similar to the embodiments of FIGS.22A-D and 23A-D. In this embodiment of the invention, upper and lowerconfronting bars 342, 344, which are relatively rigid but haveflexibility, can be retained in a delivery tool so that the leading tip348 of the distraction mechanism 340 is of a duckbill structure with theleading tip 348 of both the upper and lower bars 342, 344 being beveledto form a thin leading end of the mechanism 340 which can be insertedinto the facet joint 36. The upper and lower bars 342, 344 can define alongitudinal channel therebetween in which a plunger 350 can be slidablydisposed and reciprocally moved with a finger grip 352 on the deliverytool. Forwardly of the plunger 350, a permanent implant 354 can bepositioned within the channel between the upper and lower bars 342, 344so that upon forward movement of the plunger 350, the implant 354 canspread the upper and lower bars 342, 344 allowing the implant 354 to bereleased from the leading end 348 of the distraction mechanism 340 andbe deposited in the facet joint 36. The upper and lower bars 342, 344can be biased toward each other by an elastic band 356 which passesaround the upper and lower bars 342, 344 forwardly of the delivery toolbut rearwardly of the leading tip 348 of the distraction mechanism 340.

Although the present invention has been described with a certain degreeof particularity, it is understood the disclosure has been made by wayof example, and changes in detail or structure may be made withoutdeparting from the spirit of the invention as defined in the appendedclaims. In particular, it is noted that several embodiments have beendescribed with particular features. It is to be understood that thefeatures of any given embodiment can be combined with features of otherembodiments and still be within the scope of the invention. For example,the elongate member of FIGS. 9A-9C has been described as a toothedmember adapted for a ratcheting action, while in other embodiments theelongate member has been described as a threaded member. Wherefunctionality allows, interchanging certain features of one embodimentwith another embodiment is within the scope of the present invention.

What is claimed is:
 1. A distraction mechanism for distracting a facetjoint, the mechanism comprising: an expandable receiving portion havingupper and lower generally planar elements operably coupled together; andan actuation device adapted to be placed between the planar elements,wherein the expandable receiving portion is configured to transitionfrom an insertion configuration to an expanded configuration by theactuation device being placed between the planar elements, and when theexpandable receiving portion is in the insertion configuration, theexpandable receiving portion is flatter than when the expandablereceiving portion is in the expanded configuration.
 2. The mechanism ofclaim 1, wherein the actuation device includes an elongated member. 3.The mechanism of claim 1, wherein the actuation device includes ablock-like member.
 4. The mechanism of claim 1, wherein the actuationdevice includes a wedge-like member.
 5. The mechanism of claim 1,wherein at least one of the planar elements includes a tapered keel. 6.The mechanism of claim 1, wherein at least one of the planar elementsincludes teeth.
 7. The mechanism of claim 1, wherein at least one of theplanar elements includes a slot.
 8. The mechanism of claim 7, whereinthe actuation device includes an elongated threaded member, the threadedmember including a thread adapted to engage the slot.
 9. The mechanismof claim 8, wherein the thread protrudes through the slot.
 10. Themechanism of claim 8, wherein he thread protrudes through the slotsufficiently to act against the mechanism backing out of the facetjoint.
 11. The mechanism of claim 1, wherein at least one of the planarelements is configured to bend around the actuation device when themechanism is implanted in the facet joint.
 12. The mechanism of claim 1,wherein, when the expandable receiving portion is in the insertionconfiguration, the expandable receiving portion is capable of beingflattened for insertion into the facet joint.
 13. The mechanism of claim1, wherein, when the expandable receiving portion is in the expandedconfiguration, the expandable receiving portion is wedge-shaped.
 14. Themechanism of claim 1, wherein at least one of the planar elementsincludes a malleable material that facilitates the at least one of theplanar elements conforming to the facet joint upon implantation.
 15. Themechanism of claim 1, wherein the upper and lower planar elements beingoperably coupled together includes the upper and lower planar elementsbeing connected at an end of the expandable receiving portion.
 16. Themechanism of claim 15, wherein the upper and lower elements areconnected at the end with a living hinge.
 17. A distraction mechanismfor distracting a facet joint including a facet surface, the mechanismcomprising: an expandable receiving portion comprising a leading end, atrailing end, a first element, a second element generally opposing thefirst element, the first element and second element operably coupledtogether, the first element comprising a slot; and an elongate membercomprising a leading portion, a trailing portion opposite the leadingportion, a thread extending along the elongate member between theleading portion and the trailing portion, and a longitudinal axisextending between the leading portion and the trailing portion, whereinthe expandable receiving portion is configured to transition from aninsertion configuration to an expanded configuration via advancement ofthe elongate member between the first and second elements such that thelongitudinal axis of the elongate member extends in a directionextending between the trailing end and the leading end of the expandablereceiving portion, the advancement of the elongate member between thefirst and second elements being facilitated via the thread engaging theslot, wherein when the expandable receiving portion is in the insertionconfiguration, the first element and second element are closer togetherat the trailing end than when the expandable receiving portion is in theexpanded configuration.
 18. The mechanism of claim 17, wherein, when theexpandable receiving portion is in the insertion configuration, theexpandable receiving portion is sufficiently flattened for insertioninto the facet joint.
 19. The mechanism of claim 18, wherein, when theexpandable receiving portion is in the insertion configuration, adistance between the first element and the second element at the leadingend is sufficiently small for insertion of the expandable receivingportion into the facet joint.
 20. The mechanism of claim 19, wherein,when the expandable receiving portion is in the insertion configuration,a distance between the first element and the second element intermediatethe leading end and trailing end is sufficiently small for insertion ofthe expandable receiving portion into the facet joint.
 21. The mechanismof claim 20, wherein, when the expandable receiving portion is in theinsertion configuration, a distance between the first element and thesecond element at the trailing end is sufficiently small for insertionof the expandable receiving portion into the facet joint.
 22. Themechanism of claim 17, wherein, when the expandable receiving portion isin the expanded configuration, the expandable receiving portion iswedge-shaped.
 23. The mechanism of claim 17, wherein the leading portioncomprises a tapered tip configured to initiate advancement of theelongate member between the first and second elements.
 24. The mechanismof claim 17, wherein the first element and the second element areoperably coupled together near the leading end.
 25. The mechanism ofclaim 24, wherein the first element and the second element are operablycoupled together near the leading end via a hinge.
 26. The mechanism ofclaim 25, wherein the hinge comprises a living hinge.
 27. The mechanismof claim 17, wherein the slot comprises multiple slots arranged in athread-like arrangement.
 28. The mechanism of claim 17, wherein at leastone of the first element or second element is a planar element.
 29. Themechanism of claim 17, wherein the thread protrudes through the slotwhen the thread engages the slot.
 30. The mechanism of claim 29, whereinthe thread protrudes through the slot sufficiently to contact the facetsurface.
 31. The mechanism of claim 17, wherein the expandable receivingportion is configured for at least some conformance to the facetsurface.
 32. The mechanism of claim 17, wherein at least one of thefirst element or second element of the expandable receiving portion isconfigured for at least some deflecting around the elongated member whenthe mechanism is implanted in the facet joint.